Miniature vaporizers for use with chemical converters and energy devices

ABSTRACT

A miniature vaporizer for effectively vaporizing a process fluid (e.g., a liquid media) in small energy system applications, such as systems employing chemical reformers and fuel cells. The vaporizer of the present invention can employ a heating medium, such as a hot exhaust generated by a power system, as the heating source for generating steam or for evaporating a fluid (e.g., liquid chemicals or fuels). The vaporizer of the invention can optionally be configured to vaporize water thereby functioning as a miniature steam generator, to evaporate a process fluid thereby functioning as a miniature evaporator or heat exchanger, or to evaporate a process fluid and mix the fluid with another medium. This evaporator/mixer configuration can be used in reformer plants where a liquid chemical or fuel (e.g., gasoline, diesel, methanol, etc.) needs to be first evaporated and mixed with steam prior to the introduction of the resultant mixture to a converter (e.g., reformor or fuel cell).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. application Ser.No. 10/095,843 filed Mar. 11, 2002, the contents of which is herebyincorporated by reference.

BACKGROUND OF THE INVENTION

Conventionally, steam is generated from a primary heat source or wasteheat, which can then be used for various industrial and commercialprocesses, such as fuel reforming processes, steam generation processes,and a myriad of other activities or processes that require processsteam. The large physical size and capacity of commercially availabledevices for generating steam render them impractical for use in manymodern, energy technologies requiring delivery of process steam in acompact and cost efficient manner.

Conventional devices that utilize heat from a waste gas stream toproduce steam and/or hot water include heat recovery boilers that may ormay not employ auxiliary heat, an example of which is the DonleeTechnologies, U.S.A., boiler Series No. HR-125 through 750-G. Thesmallest of these devices has a relatively large overall length of about5 feet, a width of about 4 feet, and a height of close to 5 feet. Thedry weight of this smallest boiler device typically exceeds one ton.Other units in the series double or triple the height, width and length,and can exceed three tons. The large size and extreme weight of thisconventional boiler is impractical for use with modern, relatively smallfuel reformers and fuel cell systems that can have system sizes not muchbigger than state-of-the-art steam generators, which are considerablysmaller than the foregoing boilers.

Conventional heat exchangers can provide heated gas or liquid, but arenot designed to produce steam for various commercial processes. Forexample, a conventional device is a spiral plate type heat exchangermanufactured by Spirec N.A., U.S.A., such as illustrated and describedin U.S. Pat. Nos. 3,705,618, 3,854,530 and 3,823,458, the contents ofwhich are incorporated herein by reference. A drawback of the heatexchangers described in the foregoing patents is that they do notgenerate steam effectively.

There hence exists a need in the art to efficiently generate steam witha device suitable for use with modern processes, power systems andcomponents. Hence, an improved modular device that can efficientlygenerate steam and perform several other functions would represent amajor improvement in the art.

SUMMARY OF THE INVENTION

The present invention is directed to a relatively small or miniaturevaporizer, which can be used effectively for vaporizing a process fluid(e.g., a liquid media) in small energy system applications, such assystems employing chemical reformers and fuel cells. The vaporizer ofthe present invention can employ a heating medium, such as a hot exhaustgenerated by a power system, as the heating source for generating steamor for evaporating a process fluid (e.g., liquid chemicals or fuels).The vaporizer of the present invention can optionally be configured tovaporize a process fluid thereby functioning as a miniature steamgenerator, to evaporate a process fluid thereby functioning as aminiature evaporator or heat exchanger, or to evaporate a process fluidand mix the process fluid with another medium. This evaporator/mixerconfiguration can be used in reformer plants where a liquid chemical orfuel (e.g., gasoline, diesel, methanol, etc.) needs to be firstevaporated and mixed with steam prior to the introduction of theresultant mixture to a converter (e.g., reformer or fuel cell). Thisinvention further describes a device that is capable of performing thecombined vaporizing and mixing function in a single unified device.

According to one aspect of the invention, a vaporizer or anevaporator/mixer suitable for use with a chemical converter includes ahousing forming a chamber, and a bundle element disposed within thechamber. The bundle element includes a conduit in fluid communicationwith one or more heat exchanging surfaces defining a confined flowvolume that does not employ or is free of a baffle.

According to another aspect of the invention, the housing is configuredto be oriented essentially in a vertical position during use. In thisposition, a process fluid can be introduced to the conduit through aninlet disposed at a bottom portion of the housing, and exits the conduitfrom an outlet located at a top portion of the housing.

According to still another aspect, the bundle element comprises amulti-sheet layer forming a heat exchanging surface, wherein themulti-sheet layer is wrapped about and disposed in fluid communicationwith the conduit. The multi-sheet layer is sealed along selected outeredges.

According to still another aspect, one or more sheets of the multi-sheetlayer include surface features, such as generally parallel rows ofdimples or corrugations.

According to yet another aspect, the heat exchanging surfaces comprise aplurality of sheets, at least one of the sheets having surface featuresforming spacers for separating the sheets from each other to form flowpassages.

According to another aspect, the bundle element comprises a plurality oftubes disposed within the conduit, wherein a wall of at least one of theplurality of tubes and the conduit forms the heat exchanging surface.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features and advantages of theinvention will be apparent from the following description and apparentfrom the accompanying drawings, in which like reference characters referto the same parts throughout the different views. The drawingsillustrate principles of the invention.

FIG. 1A is a cross-sectional perspective view of a vaporizer accordingto the teachings of the present invention.

FIG. 1B is a perspective view, partially cut away, of the bundle elementof FIG. 1A illustrating the multi-sheet layer and the conduit componentsthereof. FIG. 1C is a perspective view of the bundle element of FIG. 1Bwhen the multi-sheet layer is wrapped about the conduit.

FIGS. 2A through 2C are varying views of a conventional heat exchangeremploying a baffle and non-parallel surface features formed on a sheet.

FIG. 3A is a perspective view of an alternate embodiment of thevaporizer of the invention configured as a co-axial evaporator/mixer.

FIG. 3B is a cross-sectional view of an alternate embodiment of thebundle element of the present invention.

FIG. 3C is a cross-sectional view of the bundle element of FIGS. 1A-1Cillustrating the multi-sheet layer wrapped around the conduit.

FIG. 4 is a partially cut-away perspective view of another embodiment ofthe vaporizer of the invention configured as an evaporator/mixer FIG. 5is a schematic block diagram of an electrochemical cogeneration andco-production system that utilizes one or more vaporizers of the presentinvention.

FIG. 6 is a partially cut-away perspective view of still anotherembodiment of the vaporizer according to the teachings of the presentinvention.

FIG. 7 is a perspective view of a system employing multiple vaporizersfluidly connected in a parallel with each other according to theteachings of the present invention.

FIG. 8 is a perspective view of another embodiment of a system employingmultiple vaporizers fluidly connected in parallel with each other forprocessing a different fluid and for mixing the fluids before exitingthe system.

FIG. 9 is a perspective view of another embodiment of a system employingmultiple vaporizers fluidly connected in series with each other forperforming vaporization and mixing functions in a cascade arrangement.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENT

The present invention describes a relatively small or miniaturevaporizer that can be sized and configured for vaporizing an inputprocess fluid, such as a liquid medium, for use by a chemical converteror an energy system. The process fluid can include water, liquidchemicals, liquid fuel, gasoline, methanol, or diesel fuel. Other typesof fluids can also be used. As used herein, the term chemical converteris intended to include any suitable structure adapted for receiving,processing or consuming a process fluid, examples of which includereformers, fuel cells, thermal control stacks, and hybrid systemsemploying multiple converters for providing multiple functions. The term“vaporizer” as used herein is intended to include any suitable heatexchanging structure adapted or configured to vaporize or evaporate aprocess fluid. The vaporizer can be particularly adapted or configuredto exchange heat between and/or mix two or more fluids or media, whileconverting a liquid into a vapor. The vaporizer of the present inventioncan optionally be designed and operated to vaporize a liquid media in amodern energy system employing one or more chemical converters. Examplesof applications or configurations of the vaporizer of the presentinvention include the use of hot exhaust generated by a power system asa heating source to generate steam or to evaporate liquid chemicals orfuels (evaporator), or the use of steam as the heat source forevaporating the liquid chemicals or fuels. Examples of a suitablevaporizer include a steam generator, a heat recovery steam generator(HRSG), a waste heat boiler, an evaporator, an evaporator/mixer, and aliquid chemical or fuel evaporator. The evaporator/mixer configurationof the vaporizer can be used in reformer plants where a liquid chemicalor fuel needs to be first evaporated and mixed with a heating medium ofsteam prior to being introduced to a chemical converter, such as areforming reactor. According to an optional practice, the vaporizer canbe configured so as to perform the combined function of vaporizing andmixing in a single, modular device.

FIG. 1A illustrates one embodiment of the vaporizer of the presentinvention. The illustrated vaporizer 10 includes a housing 12 defining achamber 28 that has an inlet 22 and an outlet 24. The housing can haveany selected shape or size, and preferably has a cylindrical shape witha diameter of about 12 inches or less. A bundle element 14 is mountedwithin the chamber 28. As used herein, the term “bundle element” isintended to include any suitable structure for allowing a process fluidto thermally interact with one or more other thermal media in thechamber. The bundle element of the present invention can include anyselected number or arrangement of components or parts, and preferablyincludes one or more heat exchanging surfaces that can have any selectedshape or configuration. For example, the bundle element can include aconduit and a multi-sheet layer which can be wrapped around the conduit,as described in further detail below. The multi-sheet layer can compriseat least two sheets forming the heat exchanging surfaces and whichdefine a confined flow volume. The bundle element can also beconstructed as a series of tubes as illustrated in FIG. 3B. In thisembodiment, the wall of the tubes forms the heat exchanging surface.

The illustrated bundle element of the present invention can optionallybe free of a fluid flow baffle that impedes or prevents a fluid fromflowing through at least part of the conduit or the overall bundleelement. According to another optional practice, the bundle element caninclude a plurality of surface features that can be arranged in anysuitable configuration, design or shape, and can preferably be arrangedin rows. Those of ordinary skill will also recognize that the inlet andthe outlet can be placed at any suitable locations along the housingother than the positions illustrated in FIG. 1A.

The illustrated bundle element 14 can include a conduit 16 that passesthrough the housing 12 and extends between an inlet 18 and an outlet 20.The inlet and outlet do not communicate directly with the chamber 28.Additionally, the bundle element 14 includes structure that forms theheat exchanging surface, such as a multi-sheet layer 26 having sheets26A and 26B that are disposed in fluid communication with the centralconduit 16, as illustrated in FIGS. 1A, 1B and 1C. One or more sheetsconstituting the multi-sheet layer 26 can include a plurality ofgenerally parallel rows 34 of surface features 32 that provide spacingwith an opposed facing sheet to form flow passages. According to onepractice, the surface features 32 can be corrugations or dimples,although other configurations and types of surface features can be used.According to one optional practice, the rows 34 are generally parallelto each other. Moreover, the sheets can optionally be free of any typeof baffles for preventing or impeding fluid flow within at least orportion of all of the conduit or multi-sheet layer. According to oneoptional practice, a separate flow spacer element can be can be includedwithin the multi-sheet layer. The flow spacer can be another sheet, orany other suitable structure for separating two or more sheets. Those ofordinary skill will also recognize that the surface features themselvescan operate as a spacer element.

The sheets 26A and 26B of the multi-sheet layer 26 can be sealed to eachother, such as by welding, along one or more selected outer edges, suchas edge 36, to form a fluid-tight confined volume or space between thesheets. This volume or space can be disposed in fluid communication withan inner lumen of the conduit 16 by one or more apertures formed alongthe length thereof. The multi-sheet layer 26 can then be wrapped aroundthe conduit 16, as illustrated in FIGS. 1C and 3C. The resulting bundleelement 14 can then be installed or mounted within the housing 12according to known techniques. The resultant vaporizer can be optionallyoriented in a vertical position during use and a process fluid isintroduced to the conduit 16 from the bottom of the vaporizer 10. Thoseof ordinary skill will readily recognize that any selected number ofsheets can be employed when constructing the bundle element 14.Moreover, those of ordinary skill will readily recognize that theconduit can be coupled, attached or permanently affixed to themulti-sheet layer 26 by known fastening techniques, such as by welding.The conduit can also be an integral part of the wrapping multi-sheetlayer. The housing 12, conduit 16 and multi-sheet layer 26 can be formedof any suitable material, such as steel or nickel containing compoundsor alloys suitable for high temperature applications. The lattermaterial exhibits better corrosion resistance properties.

The flow passages formed by the surface features 32 within themulti-sheet layer 26 and the conduit 16 form a fluid flow circuit B. Thegaps or spaces formed between facing wraps of the multi-sheet layer 26,when wrapped about the conduit, in conjunction with the chamber 28, theinlet 22 and the outlet 24 of the housing 12, form a fluid flow circuitA.

In operation, the vaporizer is preferably vertically positioned and anysuitable heating medium, such as a hot exhaust medium or steam, can beintroduced to the inlet 22 disposed at the top portion of the housing12. As illustrated in FIG. 1A, introducing the heated medium to the topof the housing 12 forms a counter flow heat exchanging scheme, which isa desired approach for superheating a vapor. The heating medium operatesas a heat source for the vaporizer. The heating medium passes throughthe fluid flow circuit A, namely through the chamber 28 and the gaps orspaces formed between the facing wraps of the multi-sheet layer 26 tothe outlet 24. Any suitable process fluid, such as water, can beintroduced to the inlet 18 of the conduit 16, which is positioned at thebottom of the vaporizer. The water flows along the interior of theconduit, and then passes through the apertures into the multi-sheetlayer 26. The multi-sheet layer has formed therein fluid flow passagesthat enable the conduit to maximize, optimize or increase the totalsurface area of the bundle element 14 that can function as the heatexchanging surface. The water being vaporized in the multi-sheet layerthen returns to the interior of the conduit through the apertures andexits at the conduit outlet 20. The water is heated when passing throughthe fluid flow circuit B by the heating medium flowing along the bundleelement in fluid flow circuit A. The sheets layer 26 of the bundleelement 14 serves as the heat transfer surface of the overall vaporizer10. Depending upon the temperature of the heating medium passing throughthe chamber 28 of circuit A, the water passing through the bundleelement 14 can be converted into steam. The illustrated vaporizer 10discharges the steam through the housing outlet 24.

The illustrated vaporizer 10 when vertically positioned during useallows the liquid introduced to the bundle element 14 to be distributedalong a bottom portion thereof by gravity. The liquid forms a poolwithin the multi-sheet layer 26. When the pooled liquid is heated by theheating medium flowing through circuit A, the liquid is converted into avapor without discharging unconverted liquid back into the conduit 16,thus achieving a pool boiling effect. Moreover, the configuration of thebundle element of the present invention is arranged so as to have alarge liquid surface area thereby avoiding the corresponding unwantedoccurrence of vapor flash phenomena.

Moreover, the vaporizer 10 of the present invention is a relativelyminiature vaporizer having relatively small dimensions that allows thevaporizer to be efficiently and easily integrated with modern powersystems and components.

Those of ordinary will readily recognize that the assignment of circuitA and circuit B as describe above with respect to the heating medium andprocess fluid are for illustration purposes only. The flow assignment ofthe two circuit can be reversed to achieve other intended purposes.

FIGS. 2A through 2C illustrate a conventional heat exchangermanufactured by Spirec N.A., U.S.A. The illustrated heat exchanger 40includes a vessel 42 defining a chamber 44 that has an inlet 46 and anoutlet 48. A spiral bundle 50 is mounted within the chamber 44. Theillustrated spiral bundle 50 includes a conduit 52 and a sheet element54. The sheet element 54 can include a plurality of surface features.The sheet element 54 includes a baffle 58 formed therealong. The baffleoperates as a flow impediment to fluid flowing along the sheet elementin order to obtain a desired flow direction. The flow path of the fluidas it traverses the sheet element 54 is illustrated by the flow patharrows 56. The sheet element 54 can include a pair of sheets that arewelded along the edges. The sheet element 54 is then wrapped around theconduit 52 in the manner illustrated in FIG. 2C to form an essentiallyU-shaped fluid flow circuit B. The spiral bundle 50 is installed in thevessel 42.

During operation, a fluid, such as water, is introduced to the inlet 60of the conduit 52. The water flows into the sheet element 54, andtravels along a relatively U-shaped route to reach the conduit outlet62. The surface feature, baffle 58, formed on the sheet element 54obstructs the collection of steam therein, and hence promotes orfacilitates the unacceptable phenomenon of vapor flashes that forceheated water to be discharged with the vapor at the conduit outlet 62.This results in improper operation of the heat exchanger 40.Consequently, the baffle plate causes the unwanted vapor flashphenomenon.

The vaporizer of the present invention, on the other hand, does notemploy a baffle, and can be constructed as shown in FIGS. 1A, 1B and 1Cas a miniature cylinder of about 2 inches in length and about 1 inch indiameter. For increased heat exchanging capacity, multiple vaporizerscan be used with the input liquid feeds connected in parallel andpositioned relatively level to ensure that the pool boiling effect isuniformly maintained throughout the group of vaporizers. By parallelconnection, the vaporizers are coupled to a common source, such as afluid manifold that supplies liquid to the each of the vaporizers. Thoseof ordinary skill will readily recognize that other types of connectionscan be employed. For example, the vaporizers can be connected in series,such that the output of one vaporizer serves as the input for anothervaporizer, which can serve as a superheater. In this arrangement, thevaporizer output can be introduced either to the conduit or the chamberof the next vaporizer. For example, a hot exhaust from a chemicalconverter can be employed as the heating medium in a vaporizer tovaporize a liquid, such as water, to form a water vapor. Subsequently,the water vapor can be introduced to another vaporizer operating as anevaporator/mixer. In this arrangement, a liquid fuel is evaporatedtherein and then mixed with the water vapor to form an output mixture.The output mixture is then supplied to the same or to another chemicalconverter, such as a reformer. This arrangement provides an effectivemeans for waste heat recovery in a power, thermal or chemical plant.Alternatively, each vaporizer can be coupled to a dedicated input liquidor medium source. The present invention also contemplates employingcombinations of the foregoing approaches and arrangements.

Moreover, the fluid flow circuit A of the present invention essentiallyoperates as a heat source by introducing a heating medium, such as a hotexhaust or steam, to the housing 12. The fluid flow circuit B introducesa process fluid or liquid to the vaporizer. When disposed in a verticalposition, the process fluid or liquid is fed from an inlet that ispositioned at a bottom of the housing. During operation, the processfluid or liquid fills the lower portion of the fluid flow circuit B bygravity. The process fluid or liquid is heated (e.g., boiled) by theheating medium passing through the fluid flow circuit A. Vapor iscollected above the liquid in the bundle element 14, and eventually isdischarged at the conduit outlet 20. This vaporizer hence assumes avertical operating position, allowing gravity to spread out the liquidto the lower portion of the bundle element, thus achieving full contactof the input liquid with the heat transfer surfaces. The unobstructedfluid passages (absence of a baffle) formed in the multi-sheet layer 26by the surface features 32 ensures simple vapor phase collection anddelivery, thus eliminating the unacceptable phenomenon of vapor flash.

The above assignments of heating medium and process fluid respectivelyto the circuit A and the circuit B is preferred. The reversedassignments will result in a less effective vaporization of the processfluid.

FIG. 3A illustrates an alternate embodiment of the vaporizer accordingto the teachings of the present invention. The illustrated vaporizer 70is adapted and configured to operate as a simple evaporator that is usedto convert a liquid chemical or fuel into a gaseous chemical or fuel.The vaporizer comprises a pair of concentric or coaxial tubes 72 and 74.For example, a first liquid medium, such as a liquid chemical or fuel,is introduced into the outer tube 74, and steam or another type ofheating medium is introduced into the inner tube 72. The heating mediumheats the liquid chemical passing through the outer tube to a degreesufficient to convert the chemical into a gaseous phase. Specifically, awall of the inner tube forms a heat exchanging surface for exchangingheat. Typically, in a reformer application, steam is used as the heatingmedium for evaporating the liquid chemical into a gaseous phase. Thesteam, as a reforming agent, is then mixed with the chemical or fuelprior to entering the reformer for further reforming action.

FIG. 3B illustrates an alternate embodiment of the bundle element 14′ ofthe present invention. The illustrated bundle element 14′ can beemployed in place of the bundle element 14 in any of the vaporizersshown and described herein, such as vaporizer 10 of FIG. 1. Theillustrated bundle element 14′ includes structure that forms heatexchanging surfaces for exchanging heat between a heating medium and aprocess fluid. The bundle element 14′ includes a conduit 16′ thatsurrounds a plurality of fluid carrying elements, such as tubes 17′. Thetubes 17′ are adapted to carry the heating medium, and the interior ofthe conduit 16′ is adapted to carry the process fluid, similar to themulti-sheet layer 26. The tubes 17′ can hence be disposed in fluidcommunication with the chamber of the vaporizer housing at the top andbottom portions of the tubes in order to be able to heat the inputprocess fluid flowing through the conduit 16′ in the manner describedabove. Hence, the walls of the tubes form the heat exchanging surfaces.The conduit 16′ can be attached, coupled or connected to the top andbottom portions of the vaporizer, which can be configured as headerplates. Hence, the header plates, the conduit 16′ and the outer surfaceof the tubes 17′ define the flow volume or space for the process fluid.Although illustrated as tubes, the fluid carrying elements can have anyselected shape. Those of ordinary skill will readily recognize that theprocess fluid can pass through the tubes 17′ rather than through theconduit 16′. The overall operation of the vaporizer of the presentinvention when employing the bundle element 14′ is as described aboveand below.

As illustrated in FIG. 4, the vaporizer of the present invention can beconfigured so as to function both as an evaporator and a mixer(evaporator/mixer configuration). The illustrated vaporizer 80 issimilar in configuration and construction as the vaporizer 10 of FIGS.1A through 1C with minor modifications. The vaporizer 80 includes acollection housing 82 that defines a chamber 84 that is sized toaccommodate a bundle element 86. The housing 82 includes an entranceport or inlet 92 for receiving a heating medium, such as steam, and anexit port or outlet 94 for discharging a mixed flow.

Similar to the vaporizer 10 of FIG. 1A, the illustrated bundle element86 includes a multi-sheet layer that is connected to and wrapped about aconduit 88 to provide heat exchanging surfaces 90. The multi-sheetlayer, when wrapped, forms spaces between the facing wraps forming flowpassages therebetween. According to the illustrated embodiment, themulti-sheet layer of the bundle element 86 is sealed along one or moreselected edges, such as the bottom edge, when disposed in a verticalposition, and remains unsealed along another edge, such as the top edgewhen disposed in the vertical position. The heating medium introduced tothe chamber 84 through the inlet 92 passes through the spaces betweenthe facing wraps forming a fluid flow circuit A. The multi-sheet layerincludes a plurality of surface features forming flow passages therein.The conduit 88 and the flow passages in the multi-sheet layer form fluidflow circuit B. The multi-sheet layer if desired can be devoid of anybaffles. The surface features can be optionally linear in shape, and canoptionally be generally parallel to each other. Those of ordinary skillwill recognize that any suitable surface feature configuration, designand shape can be employed.

The bundle element 86 is essentially similar to the bundle element 14 ofvaporizer 10 except that a portion of the bundle element (wrappingmulti-sheet layer and conduit) is removed. Specifically, the illustratedvaporizer 80 is constructed to include a truncated version of the bundleelement 14. The unsealed edge of the multi-sheet layer allows an inputprocess fluid, such as a liquid fuel, entering the conduit 88 andpassing through and out of the bundle element 86 at the unsealed edge tomix with the heating medium introduced to the chamber 84 through theinlet 92. Hence, the vaporizer 80 heats and evaporates the process fluidpassing through the bundle element 86 with the heated medium in thechamber 84 to produce a vapor that is discharged into the chamber 84.Concomitantly, the vaporizer functions as a mixer by mixing the gaseousoutput of the bundle element 86 with the heating medium (e.g., steam) inthe chamber 84 to form an output mixture. The output mixture can then beintroduced to any selected system component, such as a chemicalconverter.

The housing 82, the conduit 88 and multi-sheet layer of the bundleelement 86, can be formed of a suitable material, such as steel ornickel alloy for high temperature applications. The latter materialprovides better corrosion resistance to potential chemical attacks. Thevaporizer 80 can be operated with the unsealed edge along the topportion of the bundle element (e.g., disposed vertically upwards) or thehousing disposed vertically upwards and with the process fluid and theheating medium inlets located along a bottom portion of the vaporizer.This allows the liquid introduced to the bundle element 86 to bedistributed by gravity to form a pool within the fluid flow circuit B.The pooled liquid can achieve a pool boiling effect when heated by theheating medium in the fluid flow circuit A.

Moreover, due to the small flow spacing and the alternating mediadistribution in the bundle element 86, the media flowing in the fluidflow circuits A and B can readily and easily mix within the chamber 84at the truncated opening of the bundle element 86. The above designallows effective evaporation and mixing to be achieved within a single,integrated, compact vaporizer. The vaporizer 80 of the present inventioncan be constructed as a relatively small cylindrical device having alength of about 2 inches and a diameter of about 1 inch. Those ofordinary skill will readily recognize that the vaporizer or the housingcan have any selected shape. For increased capacity, the multiplevaporizer units can be coupled to separate fluid sources or to the samefluid source, which provides the fluid at all the units (parallelconfiguration). Moreover, the vaporizers can be vertically oriented orpositioned to ensure that the liquid introduced to the bundle element 86is forced by gravity to a bottom portion of the bundle element, where itcan be heated, boiled and converted to a gas (evaporated) by the heatingmedium to achieve a pool boiling affect.

FIG. 5 illustrates an electrochemical cogeneration system 100 employingmultiple vaporizers. Those of ordinary skill will readily recognize thatany suitable number of vaporizers can be employed. The illustratedsystem 100 is intended to be simply illustrative of the operation andinterrelationship of certain components of the foregoing system.Although illustrated with multiple different stages and components, thesystem can have any selected number of components and arrangementsthereof. The illustrated arrangement is merely illustrative and is notintended to be construed in a limiting sense.

A reforming agent 101, such as water, is introduced to a treatment stage102. The treatment stage 102 treats the water, such as to deionize it,and produces a treated output that is introduced to a vaporizer 104. Aheating medium supplied from any conventional source, typically the hotexhaust 121 of the system 100, is introduced to the vaporizer 104 andoperates to heat the treated water therein. Specifically, the vaporizer104 heats the water with the thermal energy associated with the heatingmedium and converts the treated water to steam. The steam is thenconveyed to a second vaporizer 110 that can be optionally configured asan evaporator/mixer. The steam generated by the vaporizer 104 serves asthe heating medium for the second vaporizer 110.

A fuel 106 is introduced to a fuel treatment stage 108 in order toremove selected impurities, such as sulfur. The treated fuel is thenintroduced to the second vaporizer 110 which functions as aevaporator/mixer. The vaporizer 110 evaporates the fuel (when liquid) toform a fuel vapor and then mixes the fuel vapor with the steam suppliedfrom the first vaporizer. The fuel/steam mixture is then introduced to achemical converter, such as the reformer 112. Those of ordinary skillwill readily recognize that many different combinations, numbers,arrangements, and types of vaporizers can be employed to attain areactant suitable for use with a chemical converter. Moreover, differenttypes of mixers can be employed in place of the vaporizer 110 if anevaporating function is not desired, such as when a gaseous fuel isused. The mixer can hence be any device suitable for mixing together twoor more media. Embodiments of the chemical converters and the mixerssuitable for use with the present invention are shown and described inInternational Patent Application Serial No. PCT/US01/48813, entitledMULTI-FUNCTION ENERGY SYSTEM OPERABLE AS A FUEL CELL, REFORMER, ORTHERMAL PLANT, by the inventor hereof, the contents of which are hereinincorporated by reference. The treatment stages 102 and 108 may also beconfigured to perform one or more of the following functions, includingwater deionization using a resin packed bed or a reverse osmosistechnique; fuel desulfurization using absorbers. Other treatment stageswhich can be connected to the vaporizer or the evaporator/mixer of thepresent invention may perform the following functions: producinghydrogen from carbon monoxide using a water shift catalyst bed; andpurifying hydrogen using a molecular sieve absorber of CO, C)₂, and H₂Oin a pressure or temperature swing absorption processor. The treatmentstage of the present invention can have any selected shape or size, andcan be configured to have a cylindrical shape having a diameter of 12inches or less.

The illustrated reformer 112 preferably reforms the fuel in the presenceof water vapor, the reforming agent, and a catalyst to create an outputmedium having one or more of H₂O, H₂, CO, CO₂, and possibly S. Thehydrogen and/or other components of the output medium can be introducedto a second chemical converter, such as the fuel cell 114. The fuel cell114 electrochemically converts the reformed fuel in the presence of anoxidant, such as air 120, into electricity while concomitantly producingan exhaust or output medium 118 primarily comprised of H₂O and CO₂. Thefuel cell output medium 118 can be a high temperature medium that can betransferred to any selected device or bottoming plant 116, such as to agas turbine or an HVAC unit. The air 120 can be directly supplied to thefuel cell or can be supplied to the fuel cell through a gas turbineassembly 116 or through a separate compressor. The output 122,electricity or conditioned medium from the bottoming plant assembly 116can also be used in any suitable manner known to those of ordinaryskill. The electricity 119 generated by the fuel cell can be extractedand used for any desired purpose. For example, the electricity 119 canbe supplied to an electrical utility grid or connection 124 and/or canbe used to charge a battery 126, such as the type employed in electricvehicles.

Those of ordinary skill will readily recognize that the vaporizer orevaporator/mixer housing can have any selected shape, configuration, orsize. In pressurized applications, the vaporizer housing, theevaporator/mixer housing and any treatment stage coupled thereto canhave a cylindrical configuration, with a diameter of about 12″ or lessin order to form a modern compact energy system.

FIG. 6 illustrates another embodiment of the vaporizer of the presentinvention. The illustrated vaporizer 130 includes a housing 132 defininga chamber 148 that has an inlet 134 and an outlet 136. A bundle element138 is mounted within the chamber 148. The illustrated bundle element138 can include a conduit system 141 that at least partially passesthrough the housing 132. The illustrated conduit system 141 includes afirst conduit portion 140 that is positioned within the chamber 148, anda second conduit portion 142 that is disposed on the outside of thehousing 132. Each of the first and second conduit portions 140 and 142extend between an inlet 144 and an outlet 146. The inlet 144 and theoutlet 146 do not communicate directly with the chamber 148.

The bundle element 138 can optionally be configured similar or identicalto the bundle elements of the invention described above, or similar oridentical to known bundle elements. For example, the bundle element 138can include a multi-sheet layer 139 that is disposed in fluidcommunication with the conduit. The multi-sheet layer can includesurface features that form flow passages therein. The multi-sheet layercan be wrapped about the conduit to form the bundle element 138. The useof baffles are optional, although it is preferred not to use them.

In operation, the vaporizer 130 is preferably vertically positioned andany suitable heating medium, such as a hot exhaust medium or steam, canbe introduced to the inlet 134 disposed at a bottom portion of thehousing 132. The heating medium operates as a heat source for thevaporizer 130. The heating medium in the chamber flows about and throughspaces formed between facing wraps of the multi-sheet layer 139. Hence,the multi-sheet layer 139 of the bundle element functions as an extendedheat exchanging surface to exchange heat between a process fluid withthe heating medium. Any suitable process fluid, such as a liquidreactant, can be introduced to the inlet 144 of the conduit, which ispositioned at the bottom portion of the vaporizer 130. The liquid flowsinto the first and second conduit portions 140 and 142, and into themulti-sheet layer 139 of the bundle element 138. The liquid isconverted, evaporated or vaporized within the first conduit portion 140and the multi-sheet layer 139 so as to form an output vapor, which isdischarged through the outlet 146. The liquid process fluid and thevaporized process fluid form a liquid-vapor interface 150 within thefirst conduit portion 140 and the multi-sheet layer 139 (e.g., withinthe bundle element). The level of the liquid within the bundle elementand/or the first conduit portion is registered in the second conduitportion 142 due to gravity. Hence, the second conduit portion 142operates as a liquid gauge or display to enable a user to determine theliquid level within the bundle element 138 and hence within thevaporizer. The second conduit portion can be made of material such asglass for liquid level visualization or of other level detection means.Moreover, the second conduit portion 142 need not be part of the bundleelement.

Furthermore, the illustrated vaporizer 130 when vertically positionedduring use allows the process fluid introduced to the bundle element 138to be distributed along a bottom portion thereof by gravity. The liquidforms a pool within the multi-sheet layer 139. When the pooled liquid isheated by the heating medium flowing through the chamber 148, the liquidis converted into vapor without discharging unwanted liquid back intothe conduit, thus achieving a pool boiling effect. The bundle element ofthe present invention avoids the corresponding unwanted occurrence ofvapor flash phenomena where liquid is accidentally discharged throughthe outlet 146.

Furthermore, the illustrated vaporizer 130 can be constructed as anevaporator/mixer by employing a truncated version of the bundle element138. The resultant unsealed edge of the multi-sheet layer 139 allows aninput process fluid, such as a liquid fuel, entering the first conduitportion 140 and passing through and out of the bundle element 138 at theunsealed edge to mix with the heating medium introduced to the chamber148 through the inlet 134. Hence, the vaporizer 130 heats and evaporatesthe process fluid passing through the bundle element 138 with the heatedmedium in the chamber 148 to produce a vapor that is discharged into thechamber 148. Concomitantly, the vaporizer functions as a mixer by mixingthe gaseous output of the bundle element 138 with the heating medium(e.g., steam)in the chamber 148 to form a output mixture. The outputmixture can then be introduced to any selected system component, such asa chemical converter.

FIG. 7 is a perspective view of a system employing multiple vaporizersfluidly connected in parallel with each other according to the teachingsof the present invention. The illustrated system 160 employs for examplea pair of vaporizers 162 and 162′. The vaporizers 162 and 162′ employbundle elements 168 and 168′, respectively. Notwithstanding the fluidarrangement of the illustrated system, the bundle elements can be any ofthe bundle elements described herein. Those of ordinary skill willreadily recognize that any selected number of vaporizers can beemployed.

As shown, the vaporizers 162 and 162′ are fluidly coupled in parallelwith each other. Specifically, an input process fluid, such as a liquidreactant, is introduced to the conduit system 170. The conduit system170 includes a pair of conduits 172 and 172′ that are coupled to acommon inlet 176 and a common outlet 178 via any suitable structuresufficient to distribute the process fluids, such as fluid manifolds.The process fluid flows into the inlet 176, and then concomitantly flowsthrough each of the separate conduits 172 and 172′ in a parallel manner.The conduits 172 and 172′ form part of the bundle elements of thepresent invention. The thermal changes and flow patterns imposed uponthe liquid once introduced to the bundle element have been describedabove and need not be repeated herein.

In operation, the vaporizers 162 and 162′ are vertically positioned andthe heating medium is introduced to the inlet 180 of the vaporizer 162and the inlet 180′ of the vaporizer 162′. The heating medium operates asa heat source for the vaporizers. The process fluid is introduced to thecommon inlet 176 of the conduit system 170. The process fluid flows intothe bundle elements 168 and 168′, and specifically into the conduits 172and 172′. The liquid is converted, evaporated or vaporized within thebundle elements so as to form a vapor reactant, which is discharged fromboth the conduits 172 and 172′through the common outlet 178. The heatingmedium exits the vaporizers at the outlets 182 and 182′. According toone practice, the heating medium has a temperature at the inlet that ishigher than the temperature at the outlet.

The heating medium exiting the vaporizer outlets 186 and 186′ can becaptured by any suitable device for subsequent use or can be vented orreleased to the ambient environment. The vapor reactant exiting thecommon outlet 178 can be transferred or conveyed to one or moreadditional vaporizers or chemical converters, or to one or more otherenergy or power system components, or can be stored in a suitablestorage container.

FIG. 8 is a perspective view of another embodiment of a system 190employing multiple vaporizers according to the teachings of the presentinvention. The system 190 employs for example a pair of vaporizers 192and 192′ that are also fluidly connected in parallel with each other. Inthis embodiment, the vaporizer 192 is configured to evaporate a firstprocess fluid, the vaporizer 192′ is configured to vaporize a secondprocess fluid, and the conduit system 218 is configured to mix theoutput streams of the vaporizers 192 and 192′. The illustratedvaporizers 192 and 192′ employ bundle elements 194 and 194′,respectively. Notwithstanding the process fluid arrangements of theillustrated conduit system 218, the bundle elements can be any of thebundle elements described herein. Those of ordinary skill will readilyrecognize that any selected number of vaporizers can be employed.Further, the vaporizers can be configured to thermally act upon theinput process fluids in ways different than those set forth herein.

As shown, the vertically positioned vaporizers 192 and 192′ are fluidlycoupled in parallel with each other. Specifically, the conduit system218 includes a conduit 196 and a conduit 196′, both of which areconnected to an intermediate connecting conduit 214. The conduits 196and 196′ form part of the bundle elements. A first process fluid, suchas a liquid fuel, is introduced to the inlet 197 of the conduit 196.Likewise, a reforming agent, such as water, is introduced to the inlet197″ of the conduit 196′. The thermal changes and flow patterns imposedupon the liquid fuel and reforming agent once introduced to the bundleelements 194 and 194′ have been described above in connection with theother embodiments and need not be repeated.

The liquid fuel introduced through the inlet 197 into the bundle element194 is vaporized by the thermal energy associated with the heatingmedium introduced to the inlet 198 of the vaporizer 192. Similarly, thereforming agent introduced through the inlet 197′ into the bundleelement 194′ is evaporated by the thermal energy associated with theheating medium introduced to the inlet 198′ of the vaporizer 192′. Theheating medium operates as a heat source for the vaporizers. The liquidsin the bundle elements 194 and 194′ are converted, evaporated orvaporized therein to form vapors, which are discharged from the conduits196 and 196′ to the common conduit portion 214. For example, thevaporizer 192 evaporates the liquid fuel to form a fuel vapor, and thevaporizer 192′ vaporizes the reforming agent to form a water vapor assteam. The vapors exiting the vaporizers 192 and 192′ are mixed withinthe common conduit portion and then discharged through the common outlet216. The heating medium exits the vaporizers at the outlets 200 and200′. According to one practice, the heating medium has a temperature atthe inlet that is higher than the temperature at the outlet.

The heating medium can be captured by any suitable device for subsequentuse or can be vented or released to the ambient environment. The mixedvapor exiting the common outlet 216 can be transferred or conveyed toone or more additional vaporizers or chemical converters, or to one ormore other energy or power system components, or can be stored in asuitable storage container.

FIG. 9 is a perspective view of another embodiment of a system employingmultiple vaporizers according to the teachings of the present invention.The illustrated system 190 employs for example a pair of vaporizers 222and 222″ that are fluidly connected in series with each other. In thisembodiment, the vaporizer 222 is configured to vaporize a first processfluid, and the vaporizer 222″ is configured to evaporate a secondprocess fluid. Moreover, the vaporizer 222″ is adapted to mix the outputstream of the vaporizer 222 with the output stream generated therein.The vaporizers 222 and 222″ employ bundle elements 224 and 224″,respectively. Notwithstanding the fluid arrangements of the illustratedconduit system 236, the bundle elements can be any of the bundleelements described herein. Those of ordinary skill will readilyrecognize that any selected number of vaporizers can be employed.Further, the vaporizers can be configured to thermally act upon theprocess fluids in ways different than those set forth herein.

As shown, the vertically positioned vaporizers 222 and 222″ are fluidlycoupled in series with each other. Specifically, the conduit system 236includes a conduit 226 that is connected to the conduit connectingportion 234. The conduit connecting portion can optionally is thencoupled to inlet chamber 230″ of the vaporizer 222″. The conduit system236 can optionally include the conduit 226″ of the bundle element 224″.

An input process fluid, such as water, is introduced to the inlet 228 ofthe conduit 226 and then eventually to the bundle element 224. A heatingmedium is introduced to the chamber 230 of the vaporizer 222, and thethermal energy associated therewith vaporizes the process fluid withinthe bundle element 224 and forms steam. The heating medium exits thevaporizer 222 at the outlet 232. The steam is transferred to the conduitconnecting portion 234, and then to the chamber 230″ of the vaporizer222″. The steam serves as the heating medium for the vaporizer 222″.

Another input process fluid, such as a liquid fuel, is introduced to theinlet 228″ of the conduit 226″. The conduit 226″ forms part of thebundle element 224″. The liquid fuel introduced through the inlet 228″into the bundle element 224″ is evaporated by the thermal energyassociated with the heating medium or the steam from the vaporizer 222to form a fuel vapor. The fuel vapor generated within the bundle element224″ is then discharged therefrom into a chamber outlet 232″ of thevaporizer 222″, where it mixes with the heating medium (steam) generatedby the first vaporizer 222. The combined fuel/steam mixture is thendischarged from the vaporizer through the outlet 232″. Those of ordinaryskill will readily recognize that the heating medium has a temperatureat the inlet of either vaporizer that is higher than the temperature atthe outlet of the vaporizer.

The thermal changes and flow patterns imposed upon the liquid fuel andwater within the bundle elements 224 and 224″ have been described aboveand need not be repeated. The heating medium exiting the vaporizer 222can be captured by any suitable device for subsequent use, can be storedin known storage containers, or can be vented or released to the ambientenvironment. The mixture exiting the outlet chamber 232″ of thevaporizer 222″ can be transferred or conveyed to one or more additionalvaporizers or chemical converters, or to one or more other energy orpower system components.

Those of ordinary skill will readily recognize that the foregoingvaporizers described in connection with all of the foregoing embodimentsof the invention are suitable for use with one or more chemicalconverters or one or more components of conventional power or energysystems.

It will thus be seen that the invention efficiently attains the objectsset forth above, among those made apparent from the precedingdescription. Since certain changes may be made in the aboveconstructions without departing from the scope of the invention, it isintended that all matter contained in the above description or shown inthe accompanying drawings be interpreted as illustrative and not in alimiting sense.

It is also to be understood that the following claims are to covergeneric and specific features of the invention described herein, and allstatements of the scope of the invention which, as a matter of language,might be the to fall therebetween.

Having described the invention, what is claimed as new and desired to besecured by Letters Patent is:

1. An energy system for producing at least one of electricity and achemical output, comprising one or more chemical converters, deliverymeans for delivering one or more fluids to the chemical converter, andone or more vaporizers of claim 1 or one or more evaporator/mixers ofclaim 28 for heating the fluid prior to introduction to the chemicalconverter.
 2. The energy system of claim 1, wherein the chemicalconverter comprises at least one of a fuel cell and a reformer.
 3. Theenergy system of claim 1, wherein the vaporizer comprises at least oneof a steam generator, a heat recovery steam generator (HRSG), a wasteheat boiler, a vaporizer, an evaporator, and an evaporator/mixer.
 4. Theenergy system of claim 1, wherein the vaporizer or the evaporator/mixercoupled to the treatment stage of the process fluid generates an outputvapor or mixture that is fluidly coupled to the chemical converter. 5.The energy system of claim 1, wherein the vaporizer is disposable duringuse in an essentially vertical position, wherein the vaporizer isadapted to vaporize water to form steam with a heating medium.
 6. Theenergy system of claim 5, wherein the vaporizer comprises a housingforming a chamber and a bundle element disposed within the chamber,wherein the water passes through the bundle element and the heatingmedium passes through the chamber.
 7. The energy system of claim 5,wherein an evaporator/mixer is fluidly coupled to the vaporizer, and thewater vaporized by the vaporizer is introduced to the evaporator/mixeras a heating medium for evaporating a liquid fuel, and for mixing theevaporated fuel with the heating medium or the steam.
 8. The energysystem of claim 1, wherein the evaporator/mixer is adapted forevaporating and mixing a process liquid with a reforming agent.
 9. Theenergy system of claim 1, wherein the evaporator/mixer is adapted forevaporating and mixing a process liquid with a heating medium.
 10. Theenergy system of claim 1, wherein the vaporizer or the evaporator/mixerincludes coaxial tubes, one of the tubes being adapted to carry aprocess fluid, and the other tubes being adapted to carry a heatingmedium, such that the heating medium transfers heat to the process fluidthrough the wall of the inner tube.